repairing a power window motor

[Faulkner]

This motor is really bugging me. I posted an inquiry to alt.engineering.electrical, and look at the reply!

http://groups.google.com/groups?q=morto ... com&rnum=1

I bet I screwed up, and have the brush bracket 90 degrees out of position! Instead of exerting maximum torque, I'm exerting minimum torque (because the armature is already in the position it would be driven to with currently constantly applied to that winding). Hope they don't take my MSEE away...

(*sigh*) Well, if at first you don't succeed...

Dan

Dan

[Faulkner]

I bet I screwed up, and have the brush bracket 90 degrees out of position! Instead of exerting maximum torque, I'm exerting minimum torque (because the armature is already in the position it would be driven to with currently constantly applied to that winding).

Great theory -- but dead wrong. The mounting rivets for the brush bracket form a rectangle, not a square. There's no way I could get it 90 degrees out of position.

But, remember that retainer I broke? Here's the pic:



Tom had said:

Hi Dan, I believe the retainer is there for assembly purposes, so it doesn't fall out, If you get the bushing off the shaft and free to turn, I would assemble the motor and not worry about the retainer. Once it's together, the bushing can't go anywhere...
Tom

For whatever reason, there was about 3/8" of play in the shaft. Tom was right -- without any play, the bushing can't go anywhere, and the armature remains centered. But with this play, the armature centers in the stator with energy applied, lifting it (and the bushing!) 3/8 of an inch, allowing the armature to move off center and bind with the stator.

I went to the hardware store, got the right size washers, played with stacking the right amount on the shaft (on the gear end, not the brush end), put power to it and...

it spins like a demon!! Forward, and reverse!!!

Lesson learned, for me. Don't give up until the fat lady sings. I spent countless hours on this d*mn thing, but I spend about $0.75 in wire and washers and came up with a working motor.

Thanks a bunch to everyone who encouraged and helped along the way.

Dan
TWSAM (The World's Slowest Auto Mechanic)

[Matthew Keij]

Don't give up until the fat lady sings

Haha! They say that all the time in the movie"Major league 2" I love that!!
Good to hear it works now. When are you putting it back in Faulker? I'll bet he is happy to have it back

[Faulkner]

I attached the motor to the regulator today -- when I tightened up the bolts that go through the motor to the assembly, the motor housing clamped to the point where the washers I had stacked on the shaft bound against the housing, and the shaft would not turn freely. I removed a washer, and now there was too much play! the bushing lifted enough to permit the shaft to move off center again, and for the armature to rub against the stator. D*mn!

But it's a beautiful day in Philly today. I started Faulkner right up, and we cruised to the local Auto Zone, where I picked up some 5/16" washers that were thinner. By substituting thin for thick, I was able to play around to the point where there was no play with the housing clamped down. The motor turns the regulator freely, no binding. Time to put the window back in.

But, what a joy to drive Faulkner! It runs like a dream, despite its 45 years. I turned heads everywhere I went. It's no creampuff like Tom's, Roger's or Ron's -- but it's mine, and I loved every minute on the road. Does it get any better than this?

Dan

[Faulkner]

...Part XII.

As TWSAM (The World's Slowest Auto Mechanic), I finally got the regulator and window back in the driver's side rear. The motor worked beautifully -- until, the star gear worked it's way out of the rubber connector, despite the tie wrap around it:



Having not fully exhausted my "washer trick", I pulled the assembly back out, put some lithium grease on the interior flat surfaces of the washers (not quite sure what lithium does to rubber), put a stack on the shaft to prevent the gear from working its way out again, replaced the tie wrap, like so:



So far, it seems to be holding up. The window goes up and down quite nicely...

Dan